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Objectives The primary objective of this systematic review was to estimate the global prevalence proportion (PP) and incidence rate (IR) of interstitial lung disease (ILD) among adults with systemic lupus erythematosus (SLE). The secondary objective was to explore possible differences in reported PP and IR of SLE-ILD between clinical and register-based studies.Methods EMBASE, MEDLINE, Cochrane Library, and Scopus were searched for eligible studies investigating SLE-ILD prevalence and/or IR. Risk of bias was assessed using the Joanna Briggs Institute Prevalence Critical Appraisal Tool, including assessment of selection bias, confounders, and external validity. Study characteristics, risk of bias assessment, and study results were described in a systematic narrative synthesis. Meta-analyses were performed using a random-effects model, and the pooled weighted prevalence and IR were calculated with 95% confidence intervals (95% CI), and visualized in forest plots. Heterogeneity was assessed with I2-test.Results We included 98 studies comprising 155,964 participants. The pooled weighted SLE-ILD prevalence was 11.0% (95% CI: 9.0-13.0%), I2 = 99.9%. Clinical studies reported a significantly higher PP of 25.0% (95% CI: 19.0%-31.0%) compared to register-based studies 7.0% (95% CI: 5.0-8.0%) ( table 1). Studies using chest high resolution CT-based diagnoses reported higher prevalence estimates, while disease duration did not affect PP. Studies including patients with pulmonary symptoms reported higher PP, though estimates were imprecise and heterogeneity remained substantial. The IR (pooled from three register-based studies among the 98 included studies) was 4.9 per 1,000 person-years (95% CI: -0.5 - 10.3) with high inconsistency between study results (I2 = 99.8%). We found no clinical studies reporting IR.Abstract PO:07:183 Table 1Subgroup analyses of 98 studies reporting on the prevalence of interstitial lung disease among patients with systemic lupus erythematosusConclusions Affecting 11%, SLE-ILD is prevalent among patients with SLE and seemingly higher among patients presenting with pulmonary symptoms. The prevalence tended to be higher in clinical studies than register-based studies, which should be considered, when interpreting results. Although the IR was low, it may be underestimated as it is based solely on three register-based studies.